Method and apparatus for underwater arc welding

ABSTRACT

According to the method of this invention water is kept away from the arc in underwater arc welding by means of a gas under a pressure greater than that of the water and, preferably, the wire-feeding unit, welding gun, and electrode wire of the gas shielded, metal arc-welding apparatus to be used under water are enclosed in airtight and watertight containers. The air connecting conduits and tubing carrying the electrode wire and shielding gas are similarly enclosed in airtight and watertight conduits. The containers and conduits are then internally pressurized with a shield gas to prevent the entry of water. The welding gun nozzle is enclosed within coaxially disposed tubular sections such that the electrode wire may be surrounded by either one or two annular gas streams under pressure which serve to shield it effectively from the surrounding water. Welding then takes place in a pocket of shielding gas to permit underwater welds of a quality previously obtainable only in atmospheric conditions. The front end of one of the tubular sections may have a flexible gasket which contacts the workpiece to aid in maintaining the pocket of shielding gas in the vicinity of the weld itself. A viewing plate is provided within the tubular section to permit the welding operation itself to be viewed while in operation. A light source and a vent tube are associated with the tubular section to facilitate the welding operation.

United States Patent 72] Inventor Ernest H. Berghof La Belle, Fla. [21] Appl. No. 886,245 [22] Filed Nov. 13, 1969 [45] Patented Jan. 4, 1972 [73] Assignee Anna Welding Corporation Continuation-impart of application Ser. No. 701,700, Jan. 30, 1968, now abandoned. This application Nov. 13, 1969, Ser. No. 886,245

[54] METHOD AND APPARATUS FOR UNDERWATER ARC WELDING 4 Claims, 12 Drawing Figs.

[52] US. Cl 219/72, 61/69 [51] Int. Cl B23k 9/16 [50] Field ofSearch 219/72, 74; 61/69; 219/131, 70

[56] References Cited UNITED STATES PATENTS 3,521,022 7/ 1970 Sadao Sato 219/72 2,572,796 10/1951 Woodard..... 219/137 2,919,341 12/1959 Roth 219/74 3,082,314 3/1963 Arata et al. 219/75 3,349,215 10/1967 Wagenleitner et al. 219/74 3,350,535 10/1967 Simon 219/74 OTHER REFERENCES The Welding Encyclopedia, Eleventh Edition, 1943, Pages 726- 728,

Primary Examiner-J. V. Truhe Assistant Examiner-Robert O'Neil Attorney-Mortenson & Weigel ABSTRACT: According to the method of this invention water is kept away from the are in underwater arc welding by means of a gas under a pressure greater than that of the water and, preferably, the wire-feeding unit, welding gun, and electrode wire of the gas shielded, metal arc-wclding apparatus to be used under water are enclosed in airtight and watertight containers. The air connecting conduits and tubing carrying the electrode wire and shielding gas are similarly enclosed in airtight and watertight conduits. The containers and conduits are then internally pressurized with a shield gas to prevent the entry of water. The welding gun nozzle is enclosed within coaxially disposed tubular sections such that the electrode wire may be surrounded by either one or two annular gas streams under pressure which serve to shield it effectively from the surrounding water. Welding then takes place in a pocket of shielding gas to permit underwater welds of a quality previously obtainable only in atmospheric conditions.

The front end of one of the tubular sections may have a flexible gasket which contacts the workpiece to aid in maintaining the pocket of shielding gas in the vicinity of the weld itself. A viewing plate is provided within the tubular section to permit the welding operation itself to be viewed while in operation. A light source and a vent tube are associated with the tubular section to facilitate the welding operation.

msmem 4:972 3.6321950 INVENT R Ernesilf. BBIyW ATTORNEYS PATENTEU JM d SHEET 2 BF 4 Ernest H. Belyhof ATTORNEYS miminm we 3.6321950 SHEET s [1F 4 mm IIIlI n Rw- 94 I 124 Ernest Berghof ATTORNEYS 156 I mvsmwz METHOD AND APPARATUS FOR UNDERWATER ARC WELDING SPECIFICATION This invention relates to gas shielding and, more particularly, to gas-shielded underwaterelectricarc welding using a consumable electrode.

BACKGROUND OF THE INVENTION At the present time underwater welds are achieved only with relatively great difficulty. In most cases, techniques employed encompass sinking a caisson over the affected area or pipe to be welded, pumping the water from within the caisson, and lowering the men and'equipment into the caisson where the welding is performed. The men and equipment then are removed, water is allowed to enter the caisson and the caisson is finally removed. This procedure is not only time consuming but is expensive.

Many efforts have been made to perform underwater welding using diving equipment. In the case of electric arc welding, coated, consumable electrodes have been developed which when consumed shield the welded area sufficiently to permit a weld of sorts. Welds, however, performed underwater using this technique, are generally unsatisfactory and not of the quality of welds obtainable above water.

It is, therefore, an object of this invention to provide for underwater welding using consumable electrodes.

Another object of this invention is to provide an improved apparatus for underwater welding using a positionable welding gun housing chamber.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT According to the preferred method of this invention, an electric are drawn between a consumable electrode and a workpiece is accomplished in underwater surroundings by forming a protective gas stream about the welding area and the weld which acts as a means for keeping the water away from the weld. One such means comprises an inner annular gas stream coaxially about the arc and forming an outer annular gas stream coaxially about the arc and the inner stream. Each of the gas streams is directed from the end portion of the electrode housing toward the workpiece, and each stream has a pressure exceeding that of the water so that it acts as a shield to prevent the water from contacting the arc and the immediate weld area on the workpiece.

To effect the above results, in one embodiment the two concentric gas streams are developed through a nozzle surrounding the end portion of the electrode and through a tubular section coaxially positioned about the nozzle to direct the two successive annular sheaths of gas. The are is established by the utilization of a source of electric power which may be floated in some boat or other apparatus above the water surface. An electrode feeding unit and the welding gun are interconnected by the conventional electrical cables and conduit for the shielding gas, and in addition, the cables and conduits are en closed within a tubular member through which additional shielding gas is pumped to protect the cables and conduits from the water and to form the outer sheath. In like manner,

the conduits and cables interconnecting the electrode feeding unit with the power supply and shielding gas supplied are enclosed within the tubular conduit which is also pressurized with the shielding gas as is the electrode feeding unit.

In a preferred embodiment of this invention a welding gun housing chamber is constructed to have first and second oppositely disposed openings, one of which serves to mount an angularly' positioned viewing plate, the other of which is.

adapted to receive a workpiece-contacting gasket which is flexible and'aids in maintaining ,the welding area free from water. A third opening in the housing chamber incorporates a flexible sealing jacket through which the welding gun itself may be inserted into the housing for welding. Shield gas is passed through a fourth opening in the housing through which opening light from a light source is directed to illuminate the work area. The shielding gas itself is passed-through a diffuser to prevent obstructing visibility within the chamber. A vent tube is rotatably mounted to the chamber at a point immediately adjacent the viewing plate to permit water and other material to be exhausted readily from the housing itself.

Using this apparatus and method, welds having the quality of dry land welds may be formed using consumable electrodes and electric arc welding techniques.

BRIEF DESCRIPTION OF THE DRAWINGS The invention, both as to its organization and method of operation, as well as additional objects and advantages thereof, will be further understood from the following description when read in connection with the accompanying drawings which are not limitative and, in which:

FIG. 1 is a sectional view denoting the overall disposition of the apparatus with reference to abody of water which apparatus is constructed in accordancewith this invention and facilitates underwater electric arc welding;

FIG. 2 is a cross-sectional view of the nozzle portion of a welding gun constructed in accordance with this invention;

FIG. 3 is a cross-sectional view taken along the section lines 3-3 of the tubular-conduit; illustrated in FIG. I, which interconnects the wire-feeding unit with the power supply and source of shielding gas;

FIG. 4 is a partial view enlarged of the welding gun and wire-feeding unit partially cut away and partially shown by dotted lines to illustrate the'detailsof the apparatus of this invention;

FIG. 5 is a top view of the wire-feeding unit seen in FIG. 4;

FIG. 6 is a side elevation view of the underwater welding gun housing chamber constructed in accordance with the preferred embodiment of this invention;

FIG. 7 is a top plan view of the welding housing chamber illustrated in FIG. 6;

FIG. 8 is an end elevation view of the welding gun housing chamber illustrated in FIG. '6;

FIG. 9 is a cross-sectional view'of the welding gun housing chamber taken throughthe section line 9-9 of FIG. 6;

FIG. 10 is a fragmented view of the welding gun housing chamber, with welding gun in operating position, taken along the section line 10-10 ofFIG. 7;

FIG. 11 is a sectional view of the welding gun housing chamber taken along the section line 11-1 1 of F IG. 7; and,

FIG. 12 is a fragmentary view of contacting gasket, used with the welding gun housing chamber, adapted tofit a cylindrical workpiece.

DETAILED DESCRIPTIONOF THE PREFERRED EMBODIMENT According to the method of this invention, underwater electric arc welding may be accomplished using gas-shielding techniques. An electric arc is drawn between an elongated consumable electrode and the workpiece, and this are is protected from the surrounding water by forming an inner annular stream of shielding gas about the electrode and then flowing this inner stream along the axis of the arc coaxially about the arc. The shielding gas may be any'of those conventionally used in gas shielded arc welding processes. Among these gases suitable for shielding are the inert gases helium, neon, argon, krypton, xenon and radon which are useful for welding of nonferrous metals. Of these inert gases, helium and argon are the most used because of their relatively low cost. Argon is typically used with l to 5 percent oxygen.

To improve the penetration pattern of the weld, carbon dioxide also may be used for either ferrous or nonferrous welding. Carbon dioxide may also he used as the shieldinggas either alone or in combination with any of the other gases. Indeed, carbon dioxide may be used as the outer shield only, the inner shield being eliminated. In many instances, the double shield is used in order to get the desired protection against chemical reaction by using the inert gases, but in instances in which chemical reaction at the weld is a minor problem or unlikely, one will use the inexpensive carbon dioxide extensively.

Whatever the shield gas employed, the outer annular gas stream is used for it is also used to protect the equipment. The outer stream is usually ejected from the welding gun nozzle. Each of the annular streams of shielding gas is generally directed from the end portion of the electrode assembly toward the workpiece and must have sufficient pressure above that of the surrounding water, to maintain the weld area and arc substantially free of water. In typical applications, welding is accomplished in water depths up to 150 feet and greater. sufficiently high-shielding gas pressures must be used to permit the flow of shielding gas into the water to protect the arc and weld area on the workpiece. In this manner, the many advantages of dry land or atmospheric electric arc welding using a shielding gas are obtained. It is also possible to lead the pressurized gas to the workpiece separately and apart from the welding gun or the wire feed. In such procedure the pressurized gas stream is generally directed across the arc and is not annular with the arc. The annular stream is preferred for convenience and ease of manipulation. Among these advantages of atmospheric arc welding are included arc stabilization, stronger welds, and others.

In alternative embodiments, the outer stream of shielding gas may be composed of air if desired, for, generally the inner sheath is generally sufficient to shield the arc itself.

The method of this invention is further described by reference to the apparatus illustrated in the drawings. in FIG. 1, for example, there is illustrated a welding machine or power source and blower 10 which is resting on the floor of a boat or barge 12. The power source 10 may comprise a conventional source which provides a generator and suitable rectification and control equipment, if desired, to provide a direct current (DC) source of power and pressurized air. This source 10 should also have such control circuitry as is necessary to provide the necessary or desired output current characteristics.

Positioned on one end of the power supply is a source of shielding gas illustrated by the reinforced cylinder 14. Running from the power supply and blower l and shielding gas supply 14 is a tubular conduit 16 which passes downwardly through the water 18 to a conventional wire feeding unit with controls illustrated by the box 20. The conduit 16, as may be noted in the cross-sectional view of FIG. 3, comprises a tube, and enclosed within the tube 16 are a power cable 22, a ground wire 24, a shielding gasline 26 and a 110 volt AC supply 28, which supplies the necessary current for the wire feed drive motor in unit 20. The shielding gas supply 14 supplies both the gasline 26 and the tube 16 with shielding gas. Alternatively, the tube 16 may be supplied with air by the blower portion of the power source or by another pressurized supply similar to the reinforced cylinder 14.

A conventional wire feeding unit and control is enclosed within the box 20. As is seen more clearly in FIG. 4, the conduit 16 is placed over a nipple 32 formed in the exterior of the box and clamped as by a band clamp 34 of conventional type (FIG. 5). The interior of the box 20 includes the wire drive 60 which is shown as a box by way of illustration only. This wire drive, as is ,well known, automatically drives the consumable elongated electrode from a supply reel 38 at a controllable, constant rate. The wire feed rate control may be on a shaft 42 extending to the top face of the box 20 and controllable as by a knob 40. The shaft 42 to which the knob is con nected may pass through a suitable watertight gasket 44 in the box 20. Handles 48 may be provided on the box to facilitate carrying. Box 20 may be formed of any suitable metal or other container capable of rough handling and may have an open upper side which is closed by a top plate 50 which may be bolted as by bolts 52 to the edges of the sides of the box 20. A sealing gasket 54 may insure a watertight seal, if necessary.

The drive for the wire or consumable electrode 94 is illustrated as the box positioned inside container 20. Connected to pass through box 60 are the several power and ground cables along the shielding gas conduit 26, these elements issuing from the conduit 16 which is connected to the inlet to box 20. Thus, the electrode wire issuing from box 60 is surrounded by the inner shielding gas as it passes to gun 64.

From the wire drive unit 60, the consumable electrode 94 passes through a guide tube 62 which contains the shielding gas from the shielding gas supply tube 26 and is connected directly to the welding gun 64 which is illustrated in dotted lines. The welding gun 64 includes a trigger switch 66 which closes a circuit in the control box 60 to actuate the wire feed. The are is established when the electrode is in proper relationship to the workpiece 70. A ground line 68 is connected from the exterior of the control box 20 to the workpiece 70 illustrated as an underwater pipe 70. The guide tube 62, as well as the welding gun 64, are enclosed within a tubular conduit 74 which is similar to the conduit 16. The conduit 74 also is placed over a nipple 96 in one side of the box 20 and clamped as by a clamp 34 to maintain a watertight connection. This permits outer shielding gas which flows through the interior of the input conduit 16 to pass into the interior of box 20, through the box 20 and through the outgoing conduit 74 to completely pressurize the entire system and, as will be described, to provide an outer shield of gas about the arc. The conduits l6 and 74 may be formed of any suitable rubber or rubberized or plastic fabric which is waterproof and impermeable and is reasonably flexible so as to permit the trigger 66 to be actuated by hand. In the alternative, the trigger switch 66 may be placed on the exterior of the conduit 74.

The welding gun 64 includes a conventional nozzle 76 (dotted lines) to which the conduit 74 is connected and is sealed as by a clamp 34. The details of the nozzle construction are seen in the enlarged view of FIG. 2, which shows the consumable electrode 94 passing through the guide tube 62 and entering the tapered tubular section 76. The flow of shielding gas from the guide tube 62 forms an inner sheath 80 about the are 82 formed between the consumable electrode 92 and the workpiece 70. This means that the actual weld 84 is surrounded by the shielding gas and chemical destruction of the metal is avoided.

if desired, to further insure the shielding of the weld 84 and are 82, the nozzle 76 is surrounded by a coaxially disposed tube section 86. This tube section is retained by the clamp 34 in sealed coaxial relationship with the tube 74 (FIG. 4). It is coaxially positioned about the nozzle 76 as by means of thumbscrews 88. The section 86 may be formed of any suitable rigid material such as a plastic or steel. This permits the shielding gas flowing through the supply tube 16, which passes through the box 20 and the tube 74, to form an outer annular sheath 90 about the inner sheath of shielding gas 80. As such, it further protects the are 82 and is permitted to bubble away peripherally from the welded area forcing water away from the working area.

The shield gas used for this outer sheath may be any of those previously described, but in addition may, for example, simply be air pumped in from the atmosphere as by the blower 10, if the expense of using shield gas for this purpose is considered too great. A chemically inactive gas is, however, preferred. The outer sheath shield gas may be a conventional shield gas and may be the same as or different than the inner sheath of shield gas.

Using the apparatus of this invention, a diver will submerge to the work area carrying along with him the wire feed and control box 20 and the welding gun. Someone on the surface will start the power supply and blower unit 10 and open the shield gas supply 14. The welder adjusts the wire feed speed,

connects the ground wire and, when ready, squeezes upon the trigger switch 66. This establishes the electric are between the consumable electrode and the workpiece. The are thus formed is protected by the double sheath of shielding gas which is permitted to escape as it forces water away so that welding takes place within a pocket of shielding gas thus providing the many advantages of welding upon dry land.

The box 20, if desired, may include a pressure-actuated switch which will deenergize the power unit in the event of a loss of pressure. A loss of pressure usually would mean that a rip in one of the tubes or a failure of the shielding gas supply occurred. The pressure-actuated switch provides a safety disconnection in the event it is deemed desirable. Additional control features may be introduced if desired. For example, control of the welding current may also be adjustable from underwater by appropriate controls. The important features of this invention are that the underwater system is under a pressurized shield gas which protects all of the equipment as well as the electrical connections from the water. Other equivalents are possible. For example, box 20 may be entirely jacketed with a cover in conduit relationship with the outer shielding gas bearing tubes. Rather than passing this gas through box 20, it is passed around and over it. In any event, the arc itself is completely shielded by a double shield of protective gas such that arc welding under water may take place as ifon dry land.

In a preferred embodiment of this invention a housing chamber adapted to provide a pocket of shield gas about the weld area and to house the tip of the welding gun itself is constructed to be generally of a hollow cylindrical shape with either end of the housing 120 defining an opening having a particular function. This housing 120 is shown in the various representations depicted in FIGS. 6-11, inclusive. The lower end of the housing (in the drawing), as is perhaps seen most clearly in FIGS. 6 and 10, has a transparent viewing plate 122. The viewing plate 122 is disposed in the lower portion of the housing 120 at an angle with respect to the axis of the cylindrical housing 120 to permit any water, welding particles, etc. to fall to the bottom, i.e., the lowermost extremity of the housing away from the central portion of the viewing plate. At this extremity, a box 124 is formed and a bore or vent tube orifice 126 is provided therein. The orifice 126 is threaded at the interior portion as at 128 to accommodate a male-threaded end 130 of a vent tube 132. The vent tube is L-shaped and has an open end and typically may be in the order of V4 to k inch in internal diameter to permit the escape of air pressure, water, welding particles, etc. as will be described hereinafter.

The viewing plate 122 is seated against a shoulder 134 formed in the interior walls of the housing 120 and is retained in place by a retaining gasket 136 which may be secured to the walls of the housing as by a plurality of screws 138.

The upper end of the housing chamber 120, as is seen in the drawings, particularly FIGS. 10 and 11, is seen to have an internal shoulder portion 140 adapted to accommodate a gasket sleeve which sleeve 142 may be removably inserted and fitted in the housing chamber 120 to be supported by the shoulder 140. A flexible gasket 144 is attached to the end face portion of the sleeve 142 to permit its contact with the welding workpiece 70 thereby to surround the immediate weld area 84. This gasket 144 may be formed of any suitable, flexible material, preferably, a porous rubber such as foam rubber or plastic. With a porous material, when the chamber 120 is pressurized, the shield gas may bubble through the gasket material and thereby prevent water from entering. Such bubbling action also facilitates and serves to lubricate the movement of the gasket material across the workpiece as the welding is accomplished. However, any flexible material capable of providing a good sealing contact with the workpiece 70 may be used.

Radial openings 150 and 152 are also formed (typically in opposite walls) of the cylinder housing chamber 120. The orifice or opening 150 formed in the right-hand wall (as seen in FIG. 10) is adapted to permit the entry of the welding gun itself. To facilitate this, a flexible sealing jacket 154 is placed over the opening and held in position by a retaining member 156 which may be secured as by screws or other suitable means to the walls of the housing 120. For this purpose, it is preferred that the opening 150 be in the form of a short length cylindrical member which may be molded contiguous with the housing 120 and radially disposed to the housing chamber 120, as perhaps seen most clearly in FIGS. 6 and 7. The particular configuration, however, is purely a function of design.

The prime requisite be that it exceed in diameter the diameter of the welding gun tip portion that is to be inserted into the housing and that the jacket 124 by flexible (rubber or suitable pliable plastic material may be used) and that it have a central opening therein of sufficient diameter to accommodate the gun itself and yet tightly engage the gun in a sealing relationship. To improve this seal the opening 157 in the jacket 154 may have an annular shoulder portion 158.

The welding gun itself may be of a conventional variety, such as that described hereinbefore, modified slightly as will be described. Thus, the gun 64 includes therein the conventional guide tube 62 which holds the consumable electrode 94 and through which shield gas from the pressurized box 20 (FIG. 4) is passed. The gun 64 is modified slightly over that described hereinbefore inasmuch as it has two switches, one switch 66 for controlling the welding current and a second switch 100 for controlling a solenoid-actuated valve which in turn controls gas flow through a clearing jet 112. The clearing jet 112, as will be described hereinafter, is positioned adjacent the gun tip and is directed to permit a short blast of shield gas to clear debris and water from the weld area. The entire gun 64 is enclosed in a sleeve or conduit 74, as described hereinbefore, which houses the various shield gaslines as well as wires or cable which carry the welding current, lighting current and switch current. These wires and conduits may be in a composite cable as is the case in ordinary welding usage or may be run individually since they are all within the outer retaining sleeve 74.

The tip of the gun 64 has an annular support member 102 which annularly encloses the guide tube 62 and consumable electrode 94. The other modification of the gun necessary is that the exterior of the support member 102 be threaded to accommodate a cap nut 106 which holds an O-ring 108 against the end portion of the support 102 to provide a seal of the annular space between the guide member 62 and the annular support member 102 which normally contains an annular insulator. The cap nut 106 has an axial opening therein which is larger than the guide member 62 to further secure, insulate, and seal it from the guide member although insulating sleeves (not shown) suitably insulate and position the guide member 62 within the annular support 102. Finally, a sealing ring 116 terminates and seals the sleeve or conduit 74 to prevent the shielding gas pressure from escaping from the shielded gun 64.

Lastly, a small radial orifice may be formed in the guide tube 62 to insure that suflicient gas may pass through and around the consumable electrode 94 and out the tip or end portion of the guide tube 62. The shield gaslines for the clearing jet 112 as well as those supplying gas to insulate the gun assembly itself all may be derived from the gas supply tube 26 (FIG. 4). In like manner, the power for the switches 66 and 100 may be derived from the electrical line 28 (FIG. 4) to control the necessary solenoid-actuated switches for controlling the welding current and the various gas supplies as required.

Shielding gas is supplied to the interior of the housing 120 through a suitable tubing (shown in phantom) 162 which in turn may be connected back to the shield gas supply tube 26 (FIG. 4) or, for that matter, directly back to the .gas supply above the surface, as desired. The shield gas supply tube 162 is terminated in a conventional fitting 164 which is connected to an orifice 166 formed in what is illustrated as a hollow cylindrical light housing cavity 168 attached or formed contiguous with the light housing 168 at the orifice 152. Shield gas from the tube 162 is allowed to pass into an annular passageway 170 formed by the housing 168 and a ringlike, radial diffuser 172. This radial diffuser has peripherally disposed openings 174 therein so that the gas may diffuse slowly into thehousing chamber from all points of the circumference of the diffuser and provide a smooth flowing path as denoted by the arrows 176 (FIG. 9). This prevents disturbing any water or other particles within the housing chamber and causingthem to swirl and blur the welders vision.

To aid in positioning the diffuser 172, a transparent light window 180 is positioned within the light housing 168. To complete this assembly, a light 182 (illustrated only symbolically) is attached to the rear portion of the light housing so as to direct its light through the window 180 and the opening 152 into the interior of the housing 120. Although illustrated as being positioned perpendicularly to the axis of the housing, it is to be noted that this light may be directed directly toward the workpiece or away therefrom as may be desired and convenient in the design of the chamber. The light, itself, is held in position by a lamp holder 184 and is attached to the light housing 168 as by screws 186 or other suitable means. A sealing gasket 188 may be used to insure a watertight seal as may be desired. Power for the light may be derived from the electrical power source leads 28 (HO. 4). Suitable switch means for the light may be provided as necessary.

To use the unique underwater welding gun housing illustrated in FIGS. 6 through 11, inclusive, the welding gun 64 is inserted through the opening 156 in the jacket 154. The light 182 is turned on and the housing 120 positioned over the joint in the workpiece 70 to be welded. Next the shield gas supplies are turned on (usually the shield gas supply through the gun itself is maintained on" to insure against the entry of water) to evacuate the water, etc. from the housing 120. Such evacuation is readily accomplished through the vent tube 132. Next the switch 100 is depressed which actuates the solenoid to pass a burst of clearing shield gas through the jet 112 directly into the weld area. This removes any residual water that might be present as well as any other dirt, particles, etc. Finally, the welding gun is positioned and as the work area is viewed through the viewing plate by the diver, the welding switch depressed, the weld is accomplished and the diver again surfaces to go to another job.

During the welding operation, as the weld is being accomplished along the bottom surface of an object, the vent tube 132 which is rotatable, is maintained in an upright position. During the time that a weld is being accomplished on a vertical surface, the vent tube 132 is maintained in a position slightly downward from the horizontal position. Similarly, when the weld is being accomplished upon a top surface, the vent tube is maintained in a downward position with respect to the surface. The adjustment of this vent tube does control to a degree the amount of shield gas that is discharged through the vent tube and may be adjusted as necessary by the welder.

It may be noted as seen most clearly in FIG. 11, that when welding a bottom surface, residual water as well as welding particles tend to fall onto the viewing plate. These, because of the sloping surface of the viewing plate, fall to the bottom most extremity of the housing where they are passed due to the flowing shield gas out through the vent tube 132. For this purpose the viewing plate may be positioned or constructed at any angle between and 90 relative to the axis of the housing 120. However, angles varying between 25 and 60 with respect to the axis are preferred. Extremely acute angles tend to obstruct the vision due to refraction and increase the required length of the housing. Conversely, angles approaching 90 do not permit the welding particles to fall off the viewing plate. The welding particles would tend to accumulate and block the vision of the welder. Appropriate sloping of the plate prevents such accumulation.

A small problem is encountered when welding underwater surfaces from the top. Specifically, the escaping shield gas bubbles tend to obstruct the welders view. This may be prevented by the simple expedient of placing a funnel over the viewing plate such that these bubbles are deflected outwardly and away from the face of the welder.

The flexible gasket 144 and its mounting sleeve 142 which is insertable by a friction fit into the end of the housing chamber 120, may have different configurations to accommodate different surfaces. Thus to accommodate a cylindrical workpiece such as a pipe 200 illustrated in FIG. 12, the flexible gasket 202 (and the sleeve 204, if necessary) may have a curvature in their plane to conform to the exterior of the pipe 200. Other configurations might include interior and exterior comers,

etc.

The invention described, using shield gases, as well as the housing which is a preferred apparatus of the invention, permits high-quality electrical welds to be accomplished underwater using either AC or DC welding current and consumable electrodes with the same quality and with almost the same facility as may be accomplished in dry land welding.

While the invention has been disclosed herein in connection with certain embodiments and certain structural and procedural details, it is clear that changes, modifications or equivalents can be used by those skilled in the art; accordingly, such changes within the principles of the invention are intended to be included within the scope of the claims below.

What is claimed is:

l. A method of underwater electric arc welding a workpiece in which an underwater electric arc is drawn between an electrode being issued from a feeding unit and said workpiece to effect welding on said workpiece and in which water is kept from contact with said arc and the weld area of said workpiece immediately adjacent said are by:

externally supplying a shielding gas under a pressure greater than the pressure of said water to said are and said weld area,

surrounding said feeding unit with a shielding gas under pressure greater than said water pressure, and

ejecting said gas as a stream about said are thereby to form an envelope about said arc and to force said water away from said arc and said weld area.

2. A method according to claim 1 which includes the step of:

forming two streams one being an inner annular gas stream coaxially about said arc and the other being an annular gas stream about said inner stream, each of said streams being directed toward said workpiece and both having a pressure exceeding that of said water, thereby to shield said arc and said weld area from said water.

3. A method in accordance with claim 2 wherein said gas 55 streams are different chemically.

4. A method according to claim 3 wherein said outer gas stream is carbon dioxide.

I IF i t i 

1. A method of underwater electric arc welding a workpiece in which an underwater electric arc is drawn between an electrode being issued from a feeding unit and said workpiece to effect welding on said workpiece and in which water is kept from contact with said arc and the weld area of said workpiece immediately adjacent said arc by: externally supplying a shielding gas under a pressure greater than the pressure of said water to said arc and said weld area, surrounding said feeding unit with a shielding gas under pressure greater than said water pressure, and ejecting said gas as a stream about said arc thereby to form an envelope about said arc and to force said water away from said arc and said weld area.
 2. A method according to claim 1 which includes the step of: forming two streams one being an inner annular gas stream coaxially about said arc and the other being an annular gas stream about said inner stream, each of said streams being directed toward said workpiece and both having a pressure exceeding that of said water, thereby to shield said arc and said weld area from said water.
 3. A method in accordance with claim 2 wherein said gas streams are different chemically.
 4. A method according to claim 3 wherein said outer gas stream is carbon dioxide. 